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Time-lapse Seismic Monitoring of Overburden Compaction due to Hydraulic Fracturing in the Montney Shale
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 77th EAGE Conference and Exhibition 2015, Jun 2015, Volume 2015, p.1 - 5
Abstract
Recent studies have shown convincing evidence that time-lapse changes in seismic data occur not only within the reservoir interval but also in the overburden. Observations that production at the reservoir level and subsequent decrease in pore pressure lead to modifications in the stress field and variations in the overburden have been documented ( Hatchell et al., 2003 ; Hudson et al., 2007 ). The study of the opposite case, that is, the analysis of the effect in the overburden of an increase in pore pressure in the reservoir, has not been so well documented yet and is the focus of this work.
The analysis is performed using multicomponent data corresponding to three seismic surveys acquired to evaluate the hydraulic stimulations of two horizontal wells in the Montney Shale.
The hypothesis is that the increase in the reservoir pressure due to the hydraulic well treatment might produce overburden compaction, leading to an increase in stresses that would be translated into an increase in the seismic velocities and therefore, into detectable time-lapse time shifts above the reservoir interval. The expectation for the compacted areas is to be correlated with zones of anisotropy in the reservoir. The results obtained from this study show evidence of this correlation.